This invention relates to an apparatus for printing characters on or punching holes in an information carrying medium, wherein a marking means for marking the medium is provided for striking or being pressed against a surface of the medium, and wherein one of the ends of an elongated arm extending mainly parallel to the surface, is equipped with or has the form of said marking means. In this apparatus the arm is resiliently connected with a frame or another support by means of a leaf spring, one portion of the leaf spring being stationary in relation to a drive device so that the arm is resiliently movable in a direction to or from the surface under the influence of the drive device.
In devices of this kind the arm and the leaf spring are connected to each other in such a way that the arm is supported by the leaf spring only at one of its sides, i.e. the joint between the arm and the spring forms an ordinary lap-joint. When the marking device on the arm strikes or presses against the information carrying medium, considerably forces arise, and these forces are transmitted directly to said joint. The joint will then be subjected to a force tending to break or pry the joint open. This has a detrimental effect on the life of the joint, and especially in high speed matrix printers, the known marking devices therefore may cause serious problems.
It is therefore an object of this invention to greatly increase the life of arrangements of the above described type by improving the joining of arm and leaf spring, so that the joint can resist greater forces than the devices known without difficulty.